This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A277547 #11 Oct 26 2016 15:24:54 %S A277547 1,2,3,4,5,6,7,8,1,1,2,3,4,5,6,7,8,2,1,2,3,4,5,6,7,8,3,1,2,3,4,5,6,7, %T A277547 8,4,1,2,3,4,5,6,7,8,5,1,2,3,4,5,6,7,8,6,1,2,3,4,5,6,7,8,7,1,2,3,4,5, %U A277547 6,7,8,8,1,2,3,4,5,6,7,8,1,1,2,3,4,5 %N A277547 a(n) = n/9^m mod 9, where 9^m is the greatest power of 9 that divides n. %C A277547 a(n) is the rightmost nonzero digit in the base 9 expansion of n. %H A277547 Clark Kimberling, <a href="/A277547/b277547.txt">Table of n, a(n) for n = 1..10000</a> %e A277547 a(11) = (11/9 mod 9) = 2. %t A277547 Table[Mod[n/9^IntegerExponent[n, 9], 9], {n, 1, 160}] %o A277547 (PARI) a(n) = n/9^valuation(n, 9) % 9; \\ _Michel Marcus_, Oct 20 2016 %Y A277547 Cf. A010878. %K A277547 nonn,easy %O A277547 1,2 %A A277547 _Clark Kimberling_, Oct 19 2016